Nomingia

Nomingia:

This theropod was the first dinosaur found with a pagnostyle - a group of fused vertebrae that formed the base for a fan of tail feathers . This fan could have been made of ornamental feathers or feathers that controlled flight . Tail fans were particularly important while flying at how speeds and during landing . However , Nomingia's tail fan was too big be used for flying , so it tail feathers were probably ornamental .